Carburetor



ocr. 25,. 193s. W, EIBING 2,134,667

GARBURETOR Filed Nov. 6, 1936 3 Sheets-Sheet 2 .Fi-g. .5

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CARB URETOR Filed Nov. 6,1936 3 Sheets-Sheet 3 um .o

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@Moc/ms Patentedv Oct.. 25,` 1938 PATENT voF-Flc-r.

cannmm'ron William E. Leibing, Detroit, Mich., assignor to LeibingAutomotive Devices, Incorporated, Detroit,l Mich., a corporatonof NevadaApplication November 6, 1936,l Serial No. 109,607

21 Claims. (Cl. 261-41) This invention relates to improvements inmethods and apparatus for operating internal combustion engines, andmore particularly to.

novel methods and means'of carbureting such engines.

Inrpresent day carburetors at `idling speed and at light loads, the fuelfed through the idling jets is not intermingled to any great extent withthe'air passing through the'intake conduit, but instead is fed only at`one side in the form of a more or less solid fuel stream while the airis supplied around the entire periphery 'ofv the carburetor.thrott1e.Obviously this results in a poor mixture. Further, it has been foundthat the butterfly valve normally employed as a throty tie which isalways at an acute angie to the axis of the conduit in which it ismounted, will at speeds where the main jets supply the fuel, divert amajor portion of the-fuel tov one wall of the conduit. All these factorscontribute to an unsatisfactory mixture, such factors being the majorcauses of ",gassing, wet manifold", unequal distribution Aand powerrumble.v

In overcoming the aforesaid disadyantages,it

is a major object of thepres'ent invention to provide a novel carburetorwhereinthe fuel mixturefis delivered. concentrically voi' the intakeconduit, and'a thorough and complete mixture is obtained at all stagesof operation including the idling and light load stages.

It is also a major object of this invention to provide a novel method ofsetting up the entering air and fuel streams so that the air as orig--inally introduced is substantially in contact with the manifold wallsuntil a complete mixture has ybeen obtained, this method being found tobe of tremendous value in eliminating gassing and insuring uniformdistribution with a consequent smooth quiet performance of the engine.

Another object of this invention resides in the provision of a novelmethod and means for insuring degassing in combination with carburetingmeans which are of relatively simple character.

'appended claims taken in connection with the accompanying drawings,wherein:

Figure 1 is a cross section of a down draft carburetor embodying myinvention' and illustrating in particular the j et for delivering fuelunder 5 light loads.

Figure 2 is an elevation of the throttle section fof Figure 1illustrating the axes for supporting the throttle blades and theconnection to the carburetor pump. l

Figure 3 is a section taken on the center line of the throttle sectionof Figure 1 illustrating the arrangement of the fuel jets andtheirr`e1ation to the throttle blades.

Figure 4l is an elevation of the connecting 15 means for the throttleblades viewed from the right side of Figure 3 with the casing covershown at the right side of Fig. 3 removed. l

Figure 5 is a section taken on a vertical line passing through theidling jet of Figure 3 and 20 looking toward the right of Figure 3.-Figure 6 is a perspective of one of the throttle blades of a.carburetor enbodying my invention.

\ Figure 'I is a bottom view of the throttle section of Figure 2. 25Figure 8 is a section of the intake conduit similar tothat shown inFigure 3 illustrating a further preferred embodiment of my invention.

'Figure 9 is a section taken at right angles to the section shown inFigure 8. 30

Figure 10 is a section of a further embodiment of my invention wherein anovel degasser is provided in combination with the carburetor of Figure1 and means is provided `-`lfor adaptation of the presentv invention tocarburetors now inuse.

Figure 11 is an elevationof a part of the device oi Figure 10 taken atright angles to Figure 10 and illustrating a novel manner of assembly ofthe units embodying my invention.

Figures 12 and' `A 13 illustrate additional modi- .40 iicgtions of thedegasserand throttle combina# tion shown in Figure 10.

Figure 14 is a-section of an updraft carburetor illustrating a" methodof combination of the degasser of my 'invention with a carburetor em'-45 ploying a throttle of the butterfly type.

Figure 15 is an elevation of the edge of the throttle of Figure .14immediately adjacent the conduit leading tothe degasser.` i

Referring to Figures 1 and 3, I have there 50 show n a preferredembodiment of my invention which may be readily, embodied in carburetorsnow being manufactured and is capable of readyv installation oncarburetors now in use.V A portion of a downdrait carburetor is shown atil duit I3, and a float chamber of the usual type generally indicated atF. A throttle housing or section I4 is provided in well known manner andconnected to conduit I3 and manifold I5 in the usual manner, a heatinsulating gasket. preferably being provided between the manifold endsection I4.

In the present invention, the conventional throttle of the buttery typeis replaced by a pair of throttle blades I1 mounted to rotate on axes I8and I9. When the intake is round, the blades are formed with a roundedouter edge. When the intake is rectangular in section or square, theouter edges of the blades are formed accordingly to effect a closurewhen in closed position. Preferably the throttle section is formed witha conduit having flattened sides as shown in Figure 'I and the throttleblades are shaped to fit. It will be noted that the blades I1 aresecured to their axes by screws 2f or similar fastening means, the axesI8 and I9 being formed half round in section and the blades `I1 securedto the upper side thereof whereby the axes do not interferewith thefluid flow over the upper surfaces of the blades I1. Axes I8 and I9 areso disposed in conduit I3 that they are each equidistant from thecenterof the conduit.

It will be noted that the blade construction described closes and opensthe conduit simultaneously at each side wall and in the center, therebygiving a three point' control of the conduit as a closure along threelines.

Each blade I1 is formed with a half round notch 22 and a half cup 23 onits inner edge as shown in Figure 6, the notches 22 cooperating to forman aperture 2l open when the blades are in closed position as shown inFigure 5, and the half cups 23 cooperating to form a closed cup '25'when the blades I1 are in closed position as shown in Figure 1.

Housing I4 is formed with a rib 26 extending thereacross and preferablyof stream-line shape as shown in Figures 1 and 5. Rib 26 is formed witha conduit 21 connecting with a fuel conduit I6 preferably connected tothe float chamber of the carburetor and opening into jets 28 and 29 thatmay be termed auxiliary jets. 'Ihe opening into jet 29 is unmetered,whllethe opening into jet 28 is preferably metered by a needle valve 3lcapable of adjustment by screw 32 in a-manner well known in the art.

It will be noted that tube 28 is of less diameter than aperture 24through which it projects when blades I1 are in closed position as shownin Figure 5, and tube 29 is of a'size and length to be entirely enclosedwithin cup 25 formed when blades I1 are in closed position as shown inFigure 1.

Assuming the device to be assembled with an engine and the engine to berunning with the blades I1 in closed position as shown in Figures 1 and5, a very low pressure equal to the pressure in the intake, manifold ofthe engine will be present on the engine side of the blades I1.Remembering that the aperture 24 is somewhat larger than jet 28, a smallamount of air at extremely high velocity will be drawn around the end ofjet 28. Since jet 28 is directly in the low pressure area, it is subjectto both the kinetic energy developed by the injector action of theincoming air around the jet and to the low pressure existing on theengine side as downstream side of the blade I1. Thus a suction of greatmagnitude is effective on the engine end of jet 28.

` with the usual venturi I2,` main fuel jet I2', con- As previouslypointed out, fuel is delivered from conduit I8 to conduit 21 and thenceto jet 28. Were a solid column of fuel brought to jet 28, it would beimpossible to adjust valve 3| satisfactorily due to the extremely lowpressure effective at the lower end of jet 28. Therefore other meansmust be employed.

As previously pointed out, as long as blades I1 are closed or nearlyclosed, cup 25 is formed (Figure 1) the mouth or open side of cup 25being toward the atmospheric side of blades I1. Jet 29, having its freeend Within cup 25 on the upstream side of the throttle is thereforeexposed to air at atmospheric pressure whenever blades I1 are closed andis free to conduct air into conj duit 21. By properly sizing jet 29 andconduit 21, any desired amount of air can be drawn into conduit 21through jet 29 to obtain a desired air-fuel ratio. Adjusting screw 32therefore permits both air and fuel to be drawn from conduit 21 throughjet 28 and the extreme sensitiveness of the above mentioned solid columnof fuel is eliminated.

A further difficult problem in carburetion has always been theprogressive movement of the throttle away from the fully closedposition. Any movement in this direction immediately requires additionalfuel. Since the pressures within the manifold are rapidly rising, amaterial problem arises in the provision of such additional fuel. Duringthis time the main jets in the carburetor are useless as they have notyet started to function.

In describing the action of blades I1 when they begin to open, let it beassumed that the engine is idling with blades I1 fully closed and thescrew 32 to be correctly adjusted to provide the correct air-fuel ratio.The action of blades I1 in correcting the mixture as the flows fall offdue to higher pressure on the engine side of blades I1 will now bedescribed.

As discussed above, jet 29 has its open end in an area of atmosphericpressure defined by cup 25 when blades I1 are closed, but as the bladesare opened, this cup is no longer at atmospheric pressure, but graduallydecreases from atmospheric pressure to the pressures equivalent to thatin the engine manifold and even below `due to the kinetic energydeveloped at the end of jet 29 betweenthe opposing ends of blades I1.Therefore by p'oper proportioning thel size of jet 29 to the diameter of`cup 25, it is obviousthat any degree of progression desired may bereadily obtained.

It is apparent to any one skilled in the art that with the presentdevice, the point of least delivery of fuel is when jet 29 has its freeend subject to atmosphericv pressure where it is free to bleed a maximumamount of air into conduit 21 and to reduce the suction on fuel line I6thereby, and it is equally apparent that any change from atmosphericpressure to a lower pressure on the jet 29 diminishes the amount of airso bled and therefore increases the actual effective pull on the fuel infuel line 21. 'I'hus even with a higher pressure in the intake manifold,the fuel fed therein is increased.

This function of jets 28 and 29 is better appreciated when it isconsidered that modern carburetors have their main jets so designedthatthey supply only approximately 30% to 40% of the fuel at speedsequal to 2000 to 3000 R. P. M. It is therefore apparent that anyimprovement in atomization and therefore distribution in the manifold,orI any improvement in the method of obtaining the throttle progressionis of extreme importance. Further, any improvement in atomization inclosed throttle position is of extreme importance to eliminate gassingfor it has been repeatedly proved that gassing is'caused primarily by awet mixture and therefore a wet manifold, the manifold in fact oftencontaining pools of raw fuel which boil out with extreme rapidity underthe low pressures caused by de` celeration. This boiling off causes themixture to become rich to an extent that it cannot be consumed by theengine .and as a consequence, the engine exhausts this obnoxious gas.

As previously explained, blades I1 are allowed to come tightly togetherat closed throttle when aperture 24 will supply about 90% of the air relquired by the engine. l'Ihe balance of air neces- -At the same .time anannular ring of air defined by the outer edgesy of the blades is formedin a manner whereby the wet mixture is insulated from the conduit wallsuntil the air and fuel have lbecome a substanially homogeneous colloidalgaseous mixture of fuel particles suspended in air.

The ends of both shafts I8 and I9 as viewed inFigure 4 extend throughbearings in housing I4 and are squared, keyed, or otherwise shaped ontheir outer ends to receive geared segments 36 and 31, so that theblades I1 operate in unison and in opposite directions of rotation.Either shaft I8 or I9 is extended as at 36 for connectionv to thethrottle of the engine. The opposite end of either shaft I8 and I9 has acrank 39 keyed thereto, a rod 4I being connected to the crank' and tothe conventional carburetor pump.

Tapped hole 42 as shown in Figure 7 is provided for receiving the sparkcontrol line. the

'smaller hole 43 connecting hole 42 with the intake conduit at a pointimmediately above one of blades I1 as shown. in Figures 1 and 5. 'I'hisposition of hole 42 is in' accordance with the usual spark controlconnectionto the carburetor throttle whereby under small movement of theblades I1 away from the closed position, the hole 42 is transferred froman atmospheric location to one subject to full engine vacuum so that theoperation ofthe sparkcontrol will be correct.

Referring to Figures 8 and 9; a further preferred modified form `of'throttle valve is there illustrated wherein 'two blades 44 pivoted asshown in Figures 1 and' 5v are formed to provide intheir closed positiona truncated conical section 45 open at its lower end as shown .inFigures 8 and 9. Disposed in this section and at a predetermineddistance from thev open bottom thereof is a jet 46 which connects with afuel conduit 41 formed in a stream-lined rib 48 extending across theconduit and controlled by a needle valve 49.

When the throttle blades 44 are in closed position, as shown in Figure9, by reason of the engine. vacuum being effective on the lower endthereof, a *considerable ow of air is induced through the open cone 45which, when the needle valve 49 is properly adjusted, draws the correctamount of fuel from jet 46 to provide a correct air fuel ratio for theengine at idling speed. An

adjustable by-pass for additional air is provided at I, a needle valve52 being provided in connection therewith.

Due to the conical shape of aperture 45, there` .44 but only to aportion thereof as determined by the distance of the end of jet 46 fromthe upper end of hollow cone '45. As the throttle valve gradually opens,the conical effect of cone 45 is gradually eliminated, and jet 46becomes exposed to the full vacuum of theuintake manifold, whichincreases the amount of fuel being drawn through the jet. This increasein the amount of fuel is accompanied by an increase in the quantity oi'air not only through the central opening of the throttle, but alsoaround the outer edges thereof so that the correct air fuel ratio ismaintained at all times. Subsequent opening of the throttle 44 'permitsthe vacuum in the intake manifold to become effective upon the main jetof the carburetor, positioned back in the venturi or adjacent theretoand not shown in Figures 8 and 9 to carry the heavier loads. This'modification is particularly desirable where it is desired to use onlyone auxiliary fuel jet.

In this modification, I have shown means whereby the throttle anddegasser and all of the modifications thereof illustrated herein may bereadily installed in existing 4carburetor in stallatlons. .InFigures 8and 9, conduit 56 may be a portion of a carburetor from which theoriginal throttle has been removed and containing a fuel supply line tothe idling jets of the carburetor. To prevent interference by thelopenings 51 for the operating shaft of .the original throttle and to usethe original fuel supply jets with my improved device, I provide asleeve 58 of a diameter to fit snugly within the original carburetorconduit 56 to seal the throttle shaft openings 51. Sleeve 58 has agroove 59 in the wall thereof forming a passage with 4the inner wall ofconduit 56 to conduct fuel from the original idling jets of thecarburetor to the new jets "of my no vel throttling device. Thisarrangement eliminates the necessity of providing new fuel supply lineswhen applying my invention to a standard carburetor since the originallines are utilized.

Itis to be understood that the sleeve arrange- Vment shown in Figures 8and 9 may be used both with the combined throttle and degasser of thisinvention and with'the throttling device of the present invention whenno degasser is employed.

.Referring to Figures 10 and 11, I have there shown a novel form ofdegasser for use with the governor and throttle of the presentinvention. As shown in Figure 10, a cross rib 26 is employed with'a fuelconduit 21', jets 28' and 29', and needle valve 3| similar to parts 26to 3l of Figure 3. The fuel conduit 21 is connected to a cross conduit53 leading into a fuel supply conduit 54 controlled by needle valve 55.

The throttle blades 6I, when in closed position, form an aperture 24 anda closed cup 25 as in the governor of Figure 1, and in addition form anaperture 62 which fits closely about a conduit 63. Conduit 63 isconnected by a con- 68 is provided in casing 66 to urge diaphragmv'l 61to the right as shown in Figure 10 with more power than can be developedin the chamber 65 by engine intake pressures. A counter-opposed spring68, adjustable by means of a screw 1| and a locknut 12, opposes the'action of spring 68 in a manner whereby at idling, the valve 55 whichis connected to diaphragm 61 through a connecting rod 13, is held by thebalance of the engine manifold pressure and springs 68 and 69 in aposition sufficiently far off its seat to permit satisfactory idling ofthe engine.

Aperturas 1l are provided in a casing 15, the latter being in threadedengagement with casing 66 to hold diaphragm 61 in the proper position.Casing 15 also serves to support adjustment member 1l.

To appreciate the value of the degasser shown, it must be rememberedthat a degasser should be rendered effective or ineffective by a verysmall movement of the throttle 6l as in the order of .010 inch. Priordegassers have always employed mechanical means to multiply thismovement, but such mechanical means have not been found satisfactorysince it is practically impossible to mechanically multiply, with.,accuracy, such small movement of the throttle blade as .010 inch in acommercial carburetor.

In the operation of the degasser shown, assuming the engine to be idlingor operating at closed throttle and the device to be correctly adjusted,the throttle substantially seals the upper end of conduit 63 when thethrottle blades are in closed position and subjects the entire lower endof the jet to the influence of the engine manifold pressures. Theadjustment of springs 68 and 69 will be such that needle valve 55 willbe sufficiently far off its seat to permit the passage of fuel necessaryto idle the engine. Thus there is no interference with the engine at itsidling speed.

If, however, the load conditions tend to drive the engine as forinstance when a car is pushing an engine during deceleration or whende-v scending a hill, the engine manifold pressure will fallsubstantially lower than that at idling. Under such conditions, anundesired amount of fuelfis drawn into the engine intake and results inso-called gassing. With the present device in proper adjustment, as thepressure in the engine manifold falls substantially lower than that atidling, this pressure is communicated through conduits 63 and 6l to theinterior of chamber 65 to move diaphragm 61 to the left and closeVneedle valve 55, thusvshutting off all fuel flow. No further fuel ow canoccur at closed throttle until the manifold pressures again equal thosefor which the adjustment was made, that is, the manifold pressure atwhich the engine will idle, which will only be when the speed of theengine again equals idling speed, at which point an even, reliablestream of idling fuel will be passed. y

A further advantage of the present degasser is evident when it isconsidered that an engine may idle 'at a vacuum of 18 inches, and stillmay have an open throttle or cracked throttle position that equals 20vinches of mercury. Obviously any balancing feature cannot functioncorrectly when these conditions are present, for when at idlingpressures of 18 inches, the device must be on the point of functioning,it is apparent that it will be operated at 20 inches. 'Ihus 20 inches ondeceleration must work the device and 20 inches in running conditionmust not work the device. 1

This situation is cared for by the present device. Assume that theenginev is idling satisfactorily at 18 inches in the manifold and thespace between conduit 63 and opening 62 in throttle 6| is closed enoughto permit of a 17 inch vacuum in the chamber 65. The springs 68 and 66are balanced to permit valve 55 to be olf its seat sufciently far topass the necessary amount of fuel for the engine. Any decrease below 18inches in the engine manifold will shut the fuel off completely. At thesame time if throttle 6| is opened 0.010 of an inch the vacuum withinchamber 65 will fall olf from 17 inches to approximately 13 inches, eventhough the manifold vacuum has increased from 18 to 21 or 22 inches.This is due to the 0.010 inch movement enlarging hole 62 around conduit63, thereby allowing more air to pass therearound and reducing theeffect of the. engine manifold vacuumv on the conduit 63 and thepressure in the chamber 65. Accordingly at cracked and all runningthrottle positions a proper supply of fuel is permitted to flow by valve55, while during deceleration when the engine vacuum exceeds the normalidling vacuum and when the throttle valve is closed, the fuel supply iscut off.

Briefly reviewing the operation of the degasser, it will be noted thatwhen the throttle is in closed position, the size of conduit 63 and thesize of aperture 62 formed by the closed throttle valve are such thatthere is no leakage of air past conduit 63 and through aperture 62, thefull manifold vacuum being effective upon diaphragm 61 in chamber 65. Atthis vacuum, springs 68 and 69are adjusted so that they maintain needlevalve 55 in open position and permit of flow of fuel to the idling jet28. Assuming that the car be driving the engine or the engine bedecelerated, a manifold vacuum above idling vacuum is created ataperture 62 which vacuum iscommunicated to the interior of chamber 65 todraw diaphragrns 61 to the left and close needle valve 55 to shut offthe fuel 110W. 'I'his operation of course occurs when the throttle valveremains in closed position.

Assuming that the throttle valve is moved toward open position and thevacuum in the intake manifold is higher than idling vacuum, aperture 62will then not be closely fitted about conduit 63 and will permitatmospheric air to flow from the upper side of the throttle through thenow enlarged aperture 62. This reduces the effect of the engine intakevacuum upon jet 63 and increases the pressure in chamber 65 to moveneedlevalve 55 to open position.

It will be noted that-the degasser is exceedingly sensitive to a veryslight movement of the throttle during a critical range, this movementof the throttle resulting in a very quick action of the degasser valveso that there is no interruption in fuel supply except when intended. Itis therefore apparent that the present invention provides a degasserwhich operates satisfactorily under all conditions of operation withoutneed of mechanical aid, the degasser being extremely sensitive andresponsive to the range of conditions within which it is designed tooperate.

In Figure 11, I have shown a preferred method of assembly of the presentinvention, the method being shown by way of example in connection withthe degasser combination. The housing 82 is formed with opposing slots83 having tapered side walls as shown. The rib 26 of Figure 3 or rim 26'of Figure 10 is formed to carry the jets i finished before they areassembled with the governor. Obviously this effects economies inmanufacture-since the ribs wouldbe diicult to maof the throttleimmediately below a conduit 16 corresponding to the conduit 83 of Figure10.

The under edges of the conduit are beveled as shown at 11 to engage theadjacent surface of the throttle. A

Figure 13 discloses a somewhat analogous modification wherein a throttleblade 18 isf shown, one' wing of which is provided with an aperture 19.Disposed immediately above aperture 19 is a conduit 8| the lower portionof which is curved so as to provide a substantially abutting engagementwith the upper surface of the throttle. Instead ofV curving conduit 8|,the lower surface thereof maybe cut transversely at an acute angle tothe' conduit axis to provide a'surface parallel to and ttlng against theadjacent surface of the throttle when closed.

In Figures 14 and 15, the degasser of my invention is shown as appliedto a carburetor ofthe updraft type with the usual throttle valve of thebutterfly type. With such types of throttles, it has been difficult toobtain satisfactory operation of the degasser since means hithertoemployed has not been suiciently sensitive to the different conditionscreated `by the throttle during its course of movement, particularlyfrom a fully closed toward open position. While prior devices haveattempted to increase the sensitivity of the degasser by mechanicalmeans primarily as by involved systems of levers and linkages, none hasproven as satisfactory in actual operation as the present degasserwherein mechanical means are almost entirely eliminated and a very fastaction of the degasser is obtained through a predetermined andrelatively slight movement of the throttle.

Referring to Figure 14, a carburetor conduit is shown at '84- with aventuri 85, and a buttery valve 86. A fuel supply line 81, preferablyleading from the float chamber of the carburetor, has a valve seat 88therein and'connects with jets 89 and 9| for feeding fuel at idling andlight loads. A diaphragm housing is provided at 92, the housing beingeither cast integral with the carburetor or secured thereto by suitablemeans. Housing 92 is provided withva cover 93 having apertures 94leading to the atmosphere, a diaphragm 95 of rubber, .Duprene or similarmaterial being secured therebetween. Springs 96 and 91 are provided onopposite sides of diavalve 99 is mounted on the right side of diaphragm95, spring 98 being adjustableby a'plug 98 threadedly mounted 'in cover93. A needle an edge of throttle 88 when closed. The point of connectionof conduit |0| is such that when throttle 88 is closed the vacuum abovethrottle 86 or' the vacuum in the engine manifold is effective upon theright side of diaphragm 95. It will be noted that the connection |02 isat the point where the throttle blade has 'a' maximum movement forapredetermined angle of oscillation. This location contributes to thesensitivity and responsiveness of the degasser.

'I'he springs 96 and 91 areso adjusted that when 4the throttle is closedand the engine is idling, the vacuum in the engine manifold isinsumcient to move the diaphragm to the right to close valve 99. Whentheengine is decelerating vor theA car is driving the. engine as whengoing down hill, the vacuum in the engine manifold` will be greater thanthat at idling and diaphragm 95 will move to the right to shut off thefuel supply to jets 89 and 9|. When throttle 88 is opened even to averyslight degree, connection |02 will be subject to the pressureeffective on the lower side of throttle 86 and diaphragm 95 will quicklymove to the left to open valve 99 and permit the freeflow of fuel tojets 89 and 9|. The quick response of diaphragm 95 is desirable toprevent an interruption in fuel ow when not desired. l l

To increase the sensitivity of the degasser, the edge of throttle 88immediately adjacent connection |02 preferably is cut away to form aknife edge |03:` Thus only a very slight movement of `or essentialcharacteristicsithereof.'i The present embodiment is therefore to beconsidered in all respects as illustrative and not restrictive, vthescope of the invention being indicated by the appended claims ratherthan by the foregoing description, and all changes which come Within themeaning and range of equivalency of the claims `are therefore intendedto` be embraced therein.

, What is claimed and desired tov be securedby ,Y

United States Letters Patent is: y

l. In a carburetor, va conduit; a venturi in said conduit; a main fueljet in said venturi; a

"the center of said conduit whereby closing of sai`d conduit along threelines is accomplished, said blades being inclined toward one another andtoward the axis of said conduit in a direction with the fluid ow; and anidling jet to introduce fuel at a point along said central line ofclosure, the inner edges of said blades-being recessed to form, anopening for said idling jet.

2. In a carburetor forran internal combustion engine, a conduit: aventuri in said conduit; a main fuel jet in 'said venturi; a throttle insaid conduit downstream of said main jet comprising a plurality ofindividual blades arranged to meet and effect a closure therebetweensubstantially along a diameter of said conduit, said blades beingpivoted on axes spaced from the conduit walls to effect closing of saidconduit along three lines; and a jetto discharge fuel for idlingpurposes into said conduit at a point substantially midway of saiddiameter, said blades in closed position deningan aperture surroundingsaid jet whereby said jet is subject to the intake manifold vacuum ofsaid engine when said throttle is closed.

3. The combination set forth in claim 2 wherein said aperture is of asize to permit a restricted iiowof air around said jet to furtherincrease the flow of fuel therefrom and atomize said fuel.

4. The combination set forth in claim 2 wherein means effective inclosed position of said throttle to mix air with said fuel prior to itsdelivery from said fuel discharge means to aidin the atomization thereofis provided, said means including a second fuel jet positioned upstreamof said blades when in closed position and subject to the pressure onthe downstream side of said blades when said blades are in openpositiOn. f

5. In a carburetor for an internal combustion engine, a conduit; athrottle in said conduit comprising a plurality of blades mounted onindividual axes and spaced from one another when in open position toprovide lines of closure at apl proximately the center of said conduitand at the sides of said conduit; and a fuel jet positionedapproximatelyv in the center of said conduit at said` central line ofclosure whereby the fuel is discharged and atomized at a pointsubstantially in the center of said conduit, said blades being arrangedto close said jet when in closed position; and an idling jet todischarge fuel into said conduit when said blades are in closedposition.

6. In a carburetor for an internal combustion engine, a conduit; athrottle in said conduit comprising a plurality of blades arranged toeffect a closure along a line passing substantially through the centerof said conduit; and a plurality of fuel jets positioned to dischargefuel adjacent said line of closure, one of said jets being positioned todischarge fuel on the downstream side of said throttle when the latterls in open or closed position, and another of said jets being positionedto be open to the upstream side' of said throttle when the latter isclosed whereby itis subject to substantially atmospheric pressure atclosed throttle position, the latter jet being transferred fromatmospheric pressure to the pressure downstream of said throttle bymovement of said throttle toward open pomtion.

7. In a, carburetor for an internal combustion engine, a conduit; athrottle in said conduit comprising a plurality of blades arranged toenect a closure on a line extending substantially through the center ofsaid conduit, each of the contacting edges of said blades comprising anotch and a half-cup section whereby in closed position said blades denean aperture of predetermined size and a cup opening against thedirection of uid flow; a fuel supply line; a jet connected t said lineextending into the aperture formed between said blades, and a second jetconnected to said line opening into said cup whereby in closed positionof said throttle, theV first jet functions to induce a flow of fuel fromsaid fuel supply line and a flow of air from said second jet.

il.l The combination claimed in claim 'l wherein means is provided toclose said fuel supply line when said throttle is in closed position andthe vacuum in the intake manifold is greater than 'predetermined normalidling vacuum compristhrottle, and when said throttle is cracked open avery slight amount, said orice is subject to a higher pressure by reasonof the pressure existlng on the upstream side of said throttle.

9. In a carburetor having a conduit therein connected to the intakemanifold of an internal combustion engine; a throttle comprising aplurality of separately pivoted blades spaced from one another when inopen position, each of a size to close approximately one-half of saidconduit and arranged to engage along a line passing through the centerof said conduit; a fuel jet adjacent the closure line of said bladeswhen in closed position whereby the flow of fuel from said jet ismetered by said throttle; a fuel supply line to said jet; pressureresponsive means to control said fuel supply line, said pressureresponsive means being connected to said conduit by a second conduithaving an orifice at a point. adjacent the closure line of said bladeswhen the latter are in closed position and arranged to be exposed to thepressure in the intake manifold when the throttle is in closed position,said means being arranged to close the fuel supply line when thethrottle is closed and the pressure in said intake manifold is belowpredetermined normal idling pressure, and to open said fuel supply linewhen said throttle moves toward open position and said orifice issubjected to higher pressure.

10. In a carburetor having a conduit connected to the intake manifold ofan internal combustion engine; a throttle comprising a plurality ofseparately pivoted blades spaced frm one another and from the sides ofsaid conduit when'in open position, each of a size to closeapproximately one-half of said conduit and arranged to engage along aline passing through' the center of said conduit whereby closing of saidconduit along three lines is accomplished; a fuel jet adjacent .thecentral closure line of said blades, said blades being notched to forman aperture in closed position permitting ow of fuel from said jet tothe downstream side of said blades; a fuel supply line to said jet;pressure responsive means to control said fuel supply line, saidpressure responsive means being connected to said conduit at a pointadjacent the central closure line of saidblades, said blades beingformed to provide an aperture in closed position connecting saidpressure responsive means to the engine vacuum and sealing saidconnection from the pressure upstream of said blades. a

11. In a carburetor for an internal combustion engine, a conduit; athrottle in said conduit; a plurality of fuel jets positioned upstreamof said throttle, said throttle being provided with an aperture toconnect at least one of said jets to its downstream side when in closedposition, said aperture being positioned and of a size to closely fitabout said jet when said throttle is in closed position to subject saidjet to substantially the full effect of the pressure downstream of saidthrottle, ,the remaining jet being subjected to the pressure upstream ofsaid throttle when the latter is in closed position.

being positioned and of a size to closely t about said jet when saidthrottle is closed; and a second jet upstream of said throttle connectedto said fuel supply line and positioned to be subject to the pressure onthe upstream side of said throttle when the latter is in closed positionwhereby in closed position of said throttle, said downstream pressurefunctions to induce a ow of fuel from said supply line and a flowof airfrom said second jet, both through said first jet. 13. The combinationclaimed in claim 12 wherein means is provided to close said fuel sup--ply line when said throttle is in closed position and the vacuum in theintake manifold lof said engine is greater than predetermined idlingvacuum comprising a pressure responsive device connected to said passageby a conduit having an orifice at a point immediately adjacent an edgeof said throttle when in closed position whereby when said throttle isin closed position, said orifice is subject to the vacuum on the engineside of said throttle and when said 'throttle is cracked open a veryslight amount, said orifice is subject to a higher pressure by reason ofthe pressure existing on the other side of said throttle.

14. In n internal combustion engine, a carburetor ha ng a passage forconveying fuel and air tp the engine; main and idling fuel supply means;a throttle for opening and closing Jsaid passage; means for shutting offthe idling fuel supply means when said throttle is at closed positionand the engine develops a vacuum in excess of predetermined normalidling vacuum, and for automatically opening said idling fuel supplymeans when said throttle is opened, said lastmentioned means comprisinga pressure responsive device connected to said passage by a conduithaving an orice at a point immediately adjacent an edge of said throttlewhen in closed position whereby when said throttle is in closedposition, said orifice is subject to the pressure `on the engine side ofsaid throttle and when said throttle is cracked open a very slightamount, said orifice is subject to a higher pressure 'because of thepressure existing on the other side of said throttle.

15. In combination with a carburetor comprising a conduit and a throttlein said conduit; idling fuel supply means; means whereby said idlingfuel supply means is shut off whenever at closed throttle the pressuredownstream of said throttle falls below predetermined normal idling orclosed throttle pressure, said means comprising pressure responsivemeans connected to said` carburetor conduit by a conduit having an oricesubject to substantially intake manifold vacuum when said throttle isclosed and positioned immediately adf valve type; an idling fuel jetadjacent one edge of said throttle whereby in closed and nearly yclosedposition the flow of fuel from said jet is meteredby said throttle; anidling fuel supply line to said jet; and pressure responsive means 5 toclose said idling fuel supply line, said pressure responsive means beingconnected to saidvcarburetor conduit by a conduit having an orificeimmediately adjacent an edge of said throttle when the latter is inclosed position and arranged 10 to be subject to the pressure in saidintake when saidthrottle is in closed position, ysaid means beingarranged to close said idling fuel supply line when said throttle isclosed and at a pressure in said intake less than the predeterminednormal 15 idling pressure, and to open said idling fuel supply line assaid throttle moves away from closed position and said orifice isthereby subjected to higher pressure.

17. In acarburetor for use with an internal 2o combustion engine, athrottle; means' adjacent an edge of said throttle when in closedposition to provide fuel when said engine is idling or operating underlight load; means to shut, oif the supply of fuel when said throttle isin closed position 25 and the vacuum downstream from said throttleexceeds that of predetermined normal idling vacuum, and means to connectsaid shut-off means to said carburetor adjacent an edge of said throttlewhen in closed position, the adjacent edge of said throttle being formedas a relatively thin section relative to the thickness of the remainderof said throttle to increase the sensitivity of 'said fuel shut-offmeans.

18. A carburetor for an internall combustion engine comprising a passagefor conducting fuel to said engine; a throttle in said passage; aconduit having an orice opening into said passage immediately adjacentan edge of said throttle when in closed position to supply fuel atidling 40 and under light load; means connected to said passage to shutoil' the flow of fuel to said supply means when said passageis closed bysaid throttle and the engine develops a vacuum in excess ofpredetermined normal idling vacuum, said throttle being positioned tocontrol said shutoff means and to meter the fuel mixture from saidsupply conduit.

19. A carburetor for an internal combustion engine comprising a passagefor conducting Vfuel to said engine; a throttle in said passage forcontrolling the iiow of fuel therethrough; a jet to supply fuel atidling and under light loads opening into said 'passage ata pointadjacent an edge of said throttle when in closed position to becontrolled by said throttle; means connected to said passage by aconduit having an orifice to shut off the flow of fuel to said jet whensaid passage is closed by said throttle and the engine develops a vacuumin excess of predetermined normal idling vacuum, said orifice beingpositioned immediately adjacent an edge of said throttle when in closedposition so that operation of said means will be dependent upon theposition of said throttle.

20. A carburetor for an internal combustion engine comprising a passagefor "conducting fuel to said engine; a throttle in said passage forcontrolling the ow of fuel therethrough; a jet for supplying fuel tosaid engine at idling and under light load; and means to shut off thefuel supply ,o

ing an orifice at a point immediately adjacent n the downstream lip ofsaidthrottle when in closed position" whereby operation of said meanswill be dependent upon the position of said throttle.

21. A carburetor for an internal combustion engine having main'andidling fuel supply means; a passage for conducting fuel to said engine;a throttle for opening and closing said passage; and means for shuttingoil* said idling fuel supply means when said throttle is at closedposition and the engine develops a vacuum in excess of `predeterminednormal idling vacuum and for automatically opening said idling fuelsupply means when said throttle opens comprising a pressure responsivedevice connected to said passage by a. conduit having an orifice at aApoint closely adjacent a portion of said throttle when in closedposition whereby said connection is connected to the engine side of saidthrottle when said throttle is in closed position, and on movement ofsaid throttle toward open position to create an opening in the order of0.01 inch, said connection is broken suilcient to render said shut-01Tmeans 10 inoperative.

WILLIAM E. LEIBING.

